The present invention relates to an arrangement for charging an accumulator of a transporting device More particularly, it relates to such an arrangement in which the transporting device is moved from one station to the other in a controlled manner and the power coupling to an external charging station is provided for the accumulator. The invention further relates to a method in which the transporting device is moved from one station to the other in a controlled manner, and the accumulator is charged via a power coupling by an external charging station.
A transfer line is known, according to EP-A 285 527, in which workpiece transport cars move from one machining station to the other on a guide path. The machining stations comprise a stopping device in each instance for stopping the workpiece transport car. The workpiece transport car is moved by means of an electric motor which draws its power from an accumulator carried along in the workpiece transport car. When the workpiece transport car is stopped in the machining station, charging contacts which are arranged at the underside of the workpiece transport car and electrically connected with the accumulator are connected with corresponding charging contacts of the charging station arranged in the machining station. The recharging of the accumulator is then effected during the machining in the machining station. No special means are indicated in the aforementioned prior publication for recharging the accumulator as a function of capacity.
It has turned out that a problem in transfer lines supplied by an accumulator consists in that the machining times in the machining stations are not always sufficient for achieving the required charging. For this reason, the dwell time of the workpiece transport car in the machining stations is often determined by the charging time required for achieving the necessary charge of the accumulator. The charging time accordingly unnecessarily prolongs the machining passage of the workpiece transport cars.
In connection with other areas of application, a plurality of arrangements and methods for implementing a recharging of accumulators as a function of the charge state are already known. In all of the known arrangements and methods of this kind the fully charged state of the accumulator is provided as a limiting value for the charging process under the criteria of a rapid charging and prevention of an overcharging of the accumulator.
These arrangements and methods for charging accumulators can accordingly not be applied to the aforementioned problems in accumulators in self-propelled workpiece transport cars in transfer lines.